PHENYLALANINE DEAMINASE AGAR SLANT-Deep TEST: Atlas page 74

Phenylalanin Deaminase agar is used to identify bacteria that have the enzyme PHENYLALANINE DEAMINASES.  This test is used to differentiate between the genera Morganella, Proteus, Provedencia (positive) as opposed to other gram negative rods which are also Enterics.

CHEMISTRY & Procedure:

This agar has a yeast extract added and DL-phenylalanine.  Microbes with the Phenylalanine Deaminase enzyme are able to deaminate DL-phenylalanine to the keto acid , phenylpyruvic acid, and free ammonia. Colorless Phenylpyruvic acid is detected by adding an oxidizing reagent to the slant after inoculation and incubation...  Then, 3-4 drops of 10% ferric chloride (FeCl3) is allowed to run down the growth area of the slant.  The resulting positive color is OLIVE GREEN.  Inoculate with a needle-stab + a loop zigzag...

Phenylalanine Deaminase Agar Slants inoculated with either Proteus, Morganella, Providencia show an OLIVE GREEN color when 10% Ferric Chloride solution is placed on the inoculated slant